source: Dev/trunk/src/client/dojox/layout/ScrollPane.js

define(["dojo/_base/kernel","dojo/_base/declare","dojo/_base/html","dojo/_base/fx",
                "dijit/_Templated","dijit/layout/ContentPane","dojo/dom-class",
                "dojo/text!./resources/ScrollPane.html"],
function(kernel,declare,html,baseFx,Templated,ContentPane,domClass,template){

kernel.experimental("dojox.layout.ScrollPane");

// FIXME: need to adjust the _line somehow, it stops scrolling

var Scrollpane = declare("dojox.layout.ScrollPane",[ContentPane, Templated],{
        // summary:
        //              A pane that "scrolls" its content based on the mouse poisition inside
        // description:
        //              A sizable container that takes it's content's natural size and creates
        //              a scroll effect based on the relative mouse position. It is an interesting
        //              way to display lists of data, or blocks of content, within a confined
        //              space.
        //
        //              Horizontal scrolling is supported. Combination scrolling is not.
        // example:
        // |    <div dojoType="dojox.layout.ScrollPane" style="width:150px height:300px;">
        // |            <!-- any height content -->
        // |    </div>
        
        // _line: dojo/_base/fx._Line
        //              storage for our top and bottom most scrollpoints
        _line: null,
        
        // _lo: 
        //              the height of the visible pane
        _lo: null,
        
        _offset: 15,
        
        // orientation: String
        //              either "horizontal" or "vertical" for scroll orientation.
        orientation: "vertical",
        
        // autoHide: Boolean
        //              whether the scroll helper should hide when mouseleave
        autoHide: true,
        templateString: template,
        
        resize: function(/*Integer?*/ size){
                // summary:
                //              calculates required sizes. Call this if you add/remove
                //              content manually, or reload the content.
                
                // if size is passed, it means we need to take care of sizing ourself (this is for IE<8)
                if(size){
                        if(size.h){
                                html.style(this.domNode,'height',size.h+'px');
                        }
                        if(size.w){
                                html.style(this.domNode,'width',size.w+'px');
                        }
                }
                var dir = this._dir,
                        vert = this._vertical,
                        val = this.containerNode[(vert ? "scrollHeight" : "scrollWidth")];

                html.style(this.wrapper, this._dir, this.domNode.style[this._dir]);
                this._lo = html.coords(this.wrapper, true);
                
                this._size = Math.max(0, val - this._lo[(vert ? "h" : "w")]);
                if(!this._size){
                        this.helper.style.display="none";
                        //make sure we reset scroll position, otherwise the content may be hidden
                        this.wrapper[this._scroll]=0;
                        return;
                }else{
                        this.helper.style.display="";
                }
                this._line = new baseFx._Line(0 - this._offset, this._size + (this._offset * 2));
        
                // share a relative position w the scroll offset via a line
                var u = this._lo[(vert ? "h" : "w")],
                        r = Math.min(1, u / val), // ratio
                        s = u * r, // size
                        c = Math.floor(u - (u * r)); // center
                          
                this._helpLine = new baseFx._Line(0, c);
        
                // size the helper
                html.style(this.helper, dir, Math.floor(s) + "px");
                
        },
        
        postCreate: function(){
                this.inherited(arguments);
                // for the helper
                if(this.autoHide){
                        this._showAnim = baseFx._fade({ node:this.helper, end:0.5, duration:350 });
                        this._hideAnim = baseFx.fadeOut({ node:this.helper, duration: 750 });
                }
        
                // orientation helper
                this._vertical = (this.orientation == "vertical");
                if(!this._vertical){
                        domClass.add(this.containerNode,"dijitInline");
                        this._dir = "width";
                        this._edge = "left";
                        this._scroll = "scrollLeft";
                }else{
                        this._dir = "height";
                        this._edge = "top";
                        this._scroll = "scrollTop";
                }

                if(this._hideAnim){
                        this._hideAnim.play();
                }
                html.style(this.wrapper,"overflow","hidden");
        
        },
        
        _set: function(/* Float */n){
                // summary:
                //              set the pane's scroll offset, and position the virtual scroll helper
                if(!this._size || n === 'focused'){ return; }
                this.wrapper[this._scroll] = Math.floor(this._line.getValue(n));
                html.style(this.helper, this._edge, Math.floor(this._helpLine.getValue(n)) + "px");
        },
        
        _calc: function(/* Event */e){
                // summary:
                //              calculate the relative offset of the cursor over the node, and call _set
                if(!this._lo){ this.resize(); }
                this._set(this._vertical ?
                        ((e.pageY - this._lo.y) / this._lo.h) :
                        ((e.pageX - this._lo.x) / this._lo.w)
                );
        },
        
        _enter: function(e){
                if(this._hideAnim){
                        if(this._hideAnim.status() == "playing"){
                                this._hideAnim.stop();
                        }
                        this._showAnim.play();
                }
        },
        
        _leave: function(e){
                if(this._hideAnim){
                        this._hideAnim.play();
                }
        } 
});
return Scrollpane;
});